Synthesis and antibacterial evaluation of some novel aminothiazole derivatives (original) (raw)
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Design, Synthesis and Antibacterial Evaluation of Some New Pyrazolinyl Bromophenylthiazoles
2018
In this study a stepwise reaction has been designed for the synthesis of some new derivatives of Pyrazolinyl bromophenylthiazoles. The progress started by the benzylation of 2,4-dihydroxyacetophenone to give 1-[2,4-bis(4-chlorobenzyloxy)phenyl]ethanone (1) which was reacted with a number of benzaldehydes to produce a series of new α,β-unsaturated carbonyl compounds (2a-j). Followed by Michael addition with thiosemicarbazide affording new pyrazolines bearing thiocarbamoyl group(3a-j). A later derivatives were treated with 4-bromophenacyl-bromide yielding a series of a target pyrazolines having a thiazole linkages(4a-j).The final products were screened for their antimicrobial evaluations using micro broth dilution method against S.aureus as gram positive and E.Coli as gram negative.Spectroscopic techniques were utilized to elucidate the structures of the prepared compounds.
Oriental journal of chemistry, 2019
In the present research we have reported simple efficient synthesis technique to afford a novel series of 3-(5-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-3-yl)-N-aryl-[1,2,4]triazolo[3,4-b][1,3,4] thiadiazol-6-amine (4a-g) derivatives obtained by one pot cyclocondensation reaction of 5-(5-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-3-yl)-4-amino-4H-1,2,4-triazole-3-thiol (3) with substituted aryl isothiocyanate in DMF and K 2 CO 3 , without formation undesirable side products by simple work up procedure. The structures yielded (4a-g) were established by 13 CNMR, IR, 1 HNMR, elemental analysis and mass spectra. Entire synthesised compounds were screened for their In vitro biological assay via microorganism Gram-positive and Gram-negative bacterial strains at different concentrations. The bioassay revealed that some of the compounds have promising antimicrobial activities when compared with standard drug Chloramphenicol.
Synthesis and Antibacterial Evaluation of Some Novel 2-Arylamino-4-phenyl-thiazolyl Derivatives
Bulletin of The Korean Chemical Society, 2010
A series of new substituted azo-pyrazolinecompounds have been synthesized and evaluated for their in vitro antimicrobial activity along with standard ciprofloxacin against gram positive Staphylococcus aureus and gram negative Klebsiellapneumoniae. The preparation of the newly azo-pyrazolinecompounds have been started by the direct diazotization of p-aminoacetophenone with o-cresol as an active coupling agent. The prepared azoacetophenone(1) was benzylated with p-chlorobenzylchloride to give benzyloxy-azochalcones (2). The later compound was reacted with a series of substituted benzaldehydesgiving a new chalcones(3a-j), which were cyclized to new pyrazolines(4a-j) by the treatment with phenylhydrazin. Finally the structures of the synthesized compounds were confirmed spectroscopically using FT-IR, 1 H-NMR, 13 C-NMR and 13 C-DEPT-135 spectra.
Journal of Heterocyclic Chemistry, 2011
A series of new substituted azo-pyrazolinecompounds have been synthesized and evaluated for their in vitro antimicrobial activity along with standard ciprofloxacin against gram positive Staphylococcus aureus and gram negative Klebsiellapneumoniae. The preparation of the newly azo-pyrazolinecompounds have been started by the direct diazotization of p-aminoacetophenone with o-cresol as an active coupling agent. The prepared azoacetophenone(1) was benzylated with p-chlorobenzylchloride to give benzyloxy-azochalcones (2). The later compound was reacted with a series of substituted benzaldehydesgiving a new chalcones(3a-j), which were cyclized to new pyrazolines(4a-j) by the treatment with phenylhydrazin. Finally the structures of the synthesized compounds were confirmed spectroscopically using FT-IR, 1 H-NMR, 13 C-NMR and 13 C-DEPT-135 spectra.
Synthesis, Antimicrobial and Antioxidant Activity of some New Pyrazolines Containing Azo Linkages
Current Organic Synthesis, 2023
In this study, various substituted chalcones, prepared by condensing substituted acetophenones with substituted aldehydes/arylfurfurals, were treated with thiosemicarbazide in basic media to produce 1-thiocarbonyl-3,5-disubstituted pyrazolines which on further reaction with substituted phenacyl bromides afforded the title compounds in good yield. Structures of the newly synthesized compounds were assigned on the basis of elemental analyses, IR, 1 H NMR, and mass spectral studies. The newly synthesized compounds were tested for their in vitro antibacterial and antifungal activities against a variety of microorganisms and antioxidant activities by diphenylpicrylhydrazyl radical scavenging assay. Among the derivatives, compounds 3b, 3e, 6a, and 6h were identified as potent antioxidants. Compounds 3d, 3e, and 6a-f have emerged as the most promising antimicrobial agents displaying the maximum activity against all the tested microorganisms.
Synthetic Communications, 2019
2-(5-(Benzo[d][1,3]dioxol-5-yl)-3-(naphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-substituted phenyl)thiazole (7) and thiazole derivatives (9) were synthesized via reaction of 4,5-dihydro-1H-pyrazoles (5a,b) with substituted phenacyl bromide and a number of a-halo-compounds respectively. Also, (E)-2-(5-(benzo[d][1,3]dioxol-5-yl)-3-(naphthalen-1-yl)-4,5 dihydro-1H-pyrazol-1-yl)-4-methyl-5-(substituted phenyldiazenyl)thiazole (11) were prepared through reactions of carbothioamide (5a,b) with hydrazonoyl halides. In addition, thioamides (5a-b) were used as starting materials for preparation of thiazoles (12a-b) and benzylidene thiazoles (13a-b). Most of synthesized compounds show interesting biological properties as antimicrobial and antiproliferative activities, the results of minimum inhibitory concentration showed that pyrazole derivative 7c (MIC: 0.23 mg/mL) showed better results when compared with 11c and 12a (MIC: 0.1-0.125 mg/mL) as obtained from their MIC values. On the other hand, 2-(5-(benzo[d][1,3]dioxol-5-yl)-3-(naphthalen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-chlorophenyl) thiazole (7c) can be considered as the most promising anti-proliferative agent against HCT-116 cancer cells owing to its notable inhibitory effect on HCT-116 cells with an IC 50 value of 6.19 mM.
Archiv Der Pharmazie, 2003
Pyrazolo[3,4-d]pyrimidines are one of the most important classes of fused heterocyclic compounds which exhibit a broad range of biological and medicinal properties. They are known as anticancer, antifungal, antibacterial, antiviral and anti-inflammatory agents. In this study, some new 6-substituted 4-amino-pyrazolo[3,4-d]pyrimidine derivatives were prepared via reaction of 5-amino-3methyl-1-phenyl-1H-pyrazole-4-carbonitrile with various nitriles in the presence of sodium ethoxide as catalyst. The inhibitory properties of synthesized compounds were studied according to CLSI guidelines against some pathogenic bacteria including four gram-positive strains (Streptococcus pyogenes, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis subsp. spizizenii) and three gramnegative strains (Pseudomonas aeruginosa, Shigella flexneri and Salmonella enterica subsp. enterica). The antibacterial effects of all derivatives were compared with those of antibiotics belonging to different classes. The values were reported as inhibition zone diameter (IZD), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The effect of substituents on the biological activity of derivatives was discussed as well. The inhibitory effect of compound 6a, was shown to be the most, with MIC values in the range of 32-4096 lg/mL. Since most of the synthesized compounds were effective against Streptococcus pyogenes and Pseudomonas aeruginosa, they can be considered as inhibitors of these two bacteria.
CHEMICAL & PHARMACEUTICAL BULLETIN, 2010
Pyrazole and its derivatives represent one of the most active classes of compounds possessing a wide spectrum of biological activities, including antibacterial, 1) antifungal, 2) herbicidal, 3) insecticidal 4) and other biological activities. Similarly, the biological activities of various 1,2,4-triazole derivatives and their N-bridged heterocyclic analogs have been widely investigated as antitumor, 8) antiviral, 9) anti-inflammatory, 10) analgesic 11) and antidepressant. 12) 1,2,4-Triazole system is also an important starting material in the synthesis of biologically active heterocycles, which constitute an important class of organic compounds with diverse biological activities, including antiparasitic, analgesic, antibacterial and anti-inflammatory activities. Further, triazole fused with other heterocyclic rings is also found to possess diverse applications in the field of medicine. The commonly known systems are triazolo-pyridines, 19) triazolo-pyridazines, 20) triazolo-pyrimidines, 21) triazolo-pyrazines, 22) triazolo-triazines 21) and triazolo-thiadiazines. 23) In addition, it has been reported that thiadiazoles exhibit a broad spectrum of biological effectiveness such as anti-parkinsonism, 24) hypoglycaemic, 25) anticancer, 26) anti-inflammatory, 27) anti-asthmatic 28) and anti-hypertensive 29) activities.
Journal of Chemistry, 2012
A number of 3-[4-(benzyloxy)-3-(2-Chlorophenylazo)-phenyl]-5-(substituted-phenyl)-1-substituted-2-pyrazolines(4a-j) and (5a-j) have been synthesized by diazotization of 2-chloroaniline and its coupling reaction with 4-hydroxy acetophenone, followed by benzyloxation of the hydroxyl group to give the substrate [4-benzyloxy-3-(2-chlorophenylazo)acetophenone (1)].The prepared starting material (1) has been reacted with different substituted benzaldehydes to give a new series of chalcone derivatives 1-[(4-benzyloxy)-3-(2-chloro-phenylazo)-phenyl]-3-(substituted phenyl)-2-propen-1-one (3a-j) , in high yields and in a few minutes, and the later compounds were treated with hydrazine hydrate according to Michael addition reaction to afford a new biolological active target compounds (4a-j) and (5a-j). Furthermore, The structures of the newly synthesized compounds were confirmed by FT-IR, 13 C-NMR, 13 C-DEPT & 1 H-NMR spectral data. The chalcone and pyrazoline derivatives were evaluated for their anti bacterial activity against Escherichia coli as gram negative and Staphylococcus aureus as gram positive, the results showed significant activity against both types of bacteria.
Synthesis, Characterization and Antibacterial activity of Benzthiazole derivatives
A parent benzothiazole nucleus was synthesized by para amino acetanilide, then it is subjected to treatment with various substituted aromatic aldehydes to get the corresponding Schiff's bases followed by treatment with pthalic anhydride to form 2-(6-acetamidobenzo[d]thiazol-2ylcarbamoyl)benzoic acid. The structures of synthesized compounds were confirmed by various spectroscopic methods such as IR, 1 H NMR and mass spectroscopy. The products were evaluated for their antibacterial activity. Some of the compounds exhibited potent activity when compared with the standards.